I have found the solution
open ccleaner
go to "options"
go to "smart cleaning"
uncheck all checkboxes ( enable smart cleaning / tell me when there are junk files to clean / enable automatic browser cleaning )
Then, go to "Updates"
uncheck all checkboxes ( keep ccleaner updated automatically / send notifications when there is a new version of ccleaner )
it works for me, the CCleaner icon in the taskbar no longer appears.